Australian embassy staff in Kabul have narrowly avoided being hit by a car bomb that exploded near their convoy as they travelled through the Afghan capital.

Foreign Minister Julie Bishop released a statement saying no Australians were injured, but local press reported a single casualty, a child selling vegetables from a cart.

Basir Mujahid, spokesman for the Kabul police chief, said the blast occurred in the neighbourhood of Qabil Bay, in an area that is home to a police station, the government's customs offices and some guest houses.

Deputy spokesman for the Interior Ministry Nasrat Rahimi said 22 people were injured in the blast.

Mohammad Musa Zahir, a doctor at the area's Wazir Akbar Khan hospital, said the injured included five children and two women.

No militant group claimed responsibility for the attack.

"The Australian Government extends its sympathies to families and friends of people killed and injured in the attack," Ms Bishop said in the statement.

"The attack highlights the threat posed by terrorist and insurgent groups to the people of Afghanistan."